The long-term goal of this research is to improve pain control and reduce aberrant behaviors and opioid analgesic addiction in persons at high risk for undertreated pain, opioid analgesic aberrant behaviors, and addiction. We propose to conduct a prospective cohort study examining the use and misuse of opioid analgesics in a community-based cohort of indigent HIV-infected adults. We propose the following specific aims: Aim 1: To determine the prevalence, characteristics and variability of pain in a community-based cohort of indigent persons with HIV infection who do and do not have a coexisting substance use disorder. Aim 2: To determine whether control of pain is predicted by the site of pain treatment (i.e., within or outside of a primary care setting) or the use of pain contracts. Aim 3: To determine predictors of aberrant opioid analgesic behaviors including the site of pain treatment (i.e., within or outside of a primary care relationship), the dosing regimen (i.e. long-acting versus short-acting), and the use of pain contracts. We will co-enroll members of the REACH cohort, a longitudinal cohort of HIV-infected adults who have high rates of illicit substance use and mental health problems, and follow them for 2 years. In addition to utilizing data collected on participants as part of REACH (health status, mental health status, and housing status), we will use four additional sources of information: quarterly structured interviews (about pain and analgesic use, misuse and substance use), urine toxicology tests, pharmacy record review, and provider interviews. Using these data sources, we will examine substance use and dependence, pain, use of prescription analgesics (including opioids), health service utilization for pain control, and rates of aberrant prescription opioid behavior. By examining the association between different strategies for controlling pain with pain and aberrant behaviors, the study will provide guidance as to the best way to treat pain safely in high-risk persons. This research will elucidate community practices regarding pain in high-risk populations and will provide guidance in how to reduce opioid analgesic aberrant behaviors and addiction. As opioid analgesic use increases, understanding the factors associated with misuse is critical. The results of this research will inform future practice to improve our understanding of risk factors for misuse and provide guidance for reducing misuse and addiction.